Rainwater Management for Smallholder Irrigation and it’s Impact on Crop Yields in Eastern India

A tank cum open dug well system suitable for plateau region of eastern India has been developed for providing reliable irrigation to croplands. The system comprises of a series of tanks with open dug wells in the recharge zone of the tank that reharvest back the seepage water. Thus, the rainwater remaining in the tank as well as partial seeped water is used for providing round the year full irrigation. This system was evaluated in field in Keonjhar district of Orissa of eastern India with six tanks and five wells in two drainage lines. The total command area of the system of six tanks and five wells in both drainage lines is 23 ha and the total irrigation potential is 44.5 ha. The total cost of the system is US $19,180 making the cost of irrigation resource creation as US $426 per ha which is much less than about $2,220 per ha for major and medium irrigation projects in the last decade of 20th century. The system increased the rice yields from 1.92 t ha^− 1 to a range of 2.25 to 3.8 t ha^− 1 depending upon the package of practices or the amount of inputs. The farmers went for crops in post-monsoon and summer season and the cropping intensity rose to 112% in the first year, 126% in the second year and 132% in the third year. The internal rate of return from the system was 13.4% at the present level of utilization, which is about 2.4% more than the prime-lending rate of Indian banks, and 3.4% more than the lending rate for agricultural purposes.     

Processing techniques for bio-based unsaturated-polyester/clay nanocomposites: Tensile properties,efficiency, and limits

Bio-based clay/polymer nanocomposites using blends of styrene-based unsaturated polyester and epoxidized methyl soyate were manufactured using solvent-based processing techniques. Four methods were evaluated to assess limitations related to solvent removal and incorporation of high clay and bio-resin content. Nanocomposite characterization was performed using electron microscopy and tensile tests. Solvent type, bio-resin addition sequence, and sonication energy were the key parameters governing processing efficiency and composite quality. Processes with bio-resin added after solvent removal show promise for the incorporation of high bio-resin and nanoclay contents. Use of acetone as a solvent with bio-resin added after solvent removal led to nanocomposites with good nanoclay dispersion and exfoliation, and high tensile modulus. Direct sonication in the base resin diluted with styrene led to enhanced and balanced gains in stiffness and toughness.     

Static and Dynamic Mechanical Properties of Vinylester Resin Matrix Composites Filled with Fly Ash

Summary: Vinylester resin matrix composites were prepared with a fly ash loading of 30, 40, 50 and 60 wt.‐%. Flexural properties of the composites were investigated. It was found that the flexural strength was lowered in all the filled composites, but the flexural modulus showed a significant increase of 10, 57, 112% in case of 30, 40 and 50 wt.‐% fly‐ash‐loaded composites respectively, compared to the neat resin. However, there was a decrease in the mechanical properties in case of 60 wt.‐% fly‐ash‐filled composites. The dynamic mechanical analysis was carried out to obtain information about the matrix‐filler interaction at the interface. The storage modulus value at room temperature was highest for the 50 wt.‐% fly‐ash‐filled composites, corroborating with the observed flexural modulus value. The fractured surfaces were examined under SEM and were correlated with the mechanical properties.

Large voids evident in the 60 wt.‐% fly‐ash‐filled composites.     

A Solvent Free Graft Copolymerization of Maleic Anhydride onto Cellulose Acetate Butyrate Bioplastic by Reactive Extrusion

Summary: Interfacial adhesion between fibers and matrix is a crucial factor for effective stress transfer from matrix to fiber; especially in short fiber reinforced composite systems. The use of a chemical compatibilizer is an efficient means to achieve such adhesion. Maleic anhydride‐grafted‐cellulose acetate butyrate (CAB‐g‐MA) is one such compatibilizer which can be used in biocomposite fabrication, and this has been synthesized in our laboratory by utilizing a twin‐screw reactive extrusion process in the presence of a free radical initiator (2,5‐dimethyl‐2,5‐di(tert‐butylperoxy)hexane). The unique feature of this process is its solvent‐free approach for grafting of maleic anhydride onto CAB, without hydroxyl group protection. CAB‐g‐MA was characterized using FTIR as well as by a non‐aqueous titration method. The effects of initiator and monomer concentrations and various processing conditions on the graft content were also investigated. The preliminary results show that by adding approximately 10 wt.‐% of CAB‐g‐MA into a plasticized cellulose acetate butyrate (TEB)‐industrial hemp fiber biocomposites system, an improvement in tensile strength (20%) and in tensile modulus (45%) were obtained. These results are promising in that they pave the way for future studies involving the use of CAB‐g‐MA as a suitable compatibilizer for cellulose ester‐natural fiber biocomposites.

     

Estimation of fuel and clad temperature of a research reactor during dry period of de-fuelling operation

Heat transfer and fluid flow studies related to spent fuel bundle of a research reactor in fuelling machine has been carried out. When the fuel is in reactor core, the heat generated in the fuel bundle is removed by heavy water under normal reactor operation. However, during the de-fuelling operation, the fuel bundle is exposed to air for some period called dry period. During this period, the decay heat from fuel bundle has to be removed by air flow. This flow of air is induced by natural convection only. In this period, the temperatures of fuel and clad rise. If clad temperature rises beyond a certain limit, structural failure may occur. This failure can result into release of fission products from fuel rod. Hence the temperature of clad has to be within specified limit under all conditions. The objective of this study is to estimate the clad temperature rise during the dry period.In the CFD simulation, the turbulent natural convection flow over fuel and radiation heat transfer are accounted. Standard k-? model for turbulence, Boussinesq approximation for computing the natural convection flow and IMMERSOL model for radiation are used.The steady state and transient CFD simulation of flow and heat is performed, using the CFD code PHOENICS. The steady state analysis provides the maximum temperature the clad will attain if fuel bundle is left exposed to air for sufficiently long time. For safe operation, the clad temperature should be limited to a specified value. From steady state CFD analysis, it is found that steady state clad temperature for various decay powers is higher than the limiting value. Hence transient analysis is also performed. In the transient analysis, the variation of clad temperature with time is predicted for various decay powers. Safe dry time, i.e. the time required for clad to reach the limiting value, is predicted for various decay powers. Determination of safe dry time helps in deciding the time available to the operator to drop the bundle in light water pool for storage. The analysis is found useful in optimizing the de-fuelling process.     

Beneficiation of High-alumina Bearing Iron-ore Slime: A Case Study From Eastern India

A typical high-alumina containing iron ore slime from the eastern Indian sector containing 58.13% Fe, 6.48% SiO₂, 4.9% Al₂O₃, and 5.35% LOI, have been evaluated to find out whether grinding of the slimes will be beneficial or not for upgrading the slime to generate pellet-grade concentrate with >64% Fe. Liberation studies indicated that there is significant interlocking between the minerals above 0.074 mm and hence grinding was adopted to liberate the minerals. It is found that by one-stage grinding, followed by hydrocycloning and magnetic separation by wet high intensity magnetic separator (WHIMS) can produce desired concentrate with >64% Fe with an yield over 60%.     

Synthesis and Microstructure Evolution of Nano-Titania Doped Silicon Coatings

The Anatase phase of Titania (TiO₂) in nanocrystalline form is a well known photocatalyst. Photocatalysts are commercially used to accelerate photoreactions and increase photovoltaic efficiency such as in solar cells. This study investigates the in-flight synthesis of Titania and its doping into a Silicon matrix resulting in a catalyst-dispersed coating. A liquid precursor of Titanium Isopropoxide and ethanol was coaxially fed into the plasma gun to form Titania nanoparticles, while Silicon powder was externally injected downstream. Coatings of 75-150 μm thick were deposited onto flat coupons. Further, Silicon powder was alloyed with aluminum to promote crystallization and reduce the amorphous phase in the Silicon matrix. Dense coatings containing nano-Titania particles were observed under electron microscope. X-ray diffraction showed that both the Rutile and Anatase phases of the Titania exist. The influence of process parameters and aluminum alloying on the microstructure evolution of the doped coatings is analyzed and presented.     

A Study on Arc Instability Phenomena of an Axial Injection Cathode Plasma Torch

Axial injection in plasma gun through the cathode has clear benefit of longer particle residence time and optimum particle trajectory in the plume; however, accelerated wear of the cathode seem to be the major issue in this approach. This study investigates the arc instability phenomena in an axially injecting single cathode plasma torch design. Gun voltage measurements were used to evaluate the arc behavior. For comparison purpose, arc fluctuations with a standard solid cathode torch design under identical operating parameters have also been studied. A comparison of different internal hardware configurations is also done to understand and establish the important factors in the design of the axial injection and solid cathode systems. Further, this study presents the influence of plume elongation and accelerated gas velocities on the arc behavior in different configurations under low pressure environment.     

Upgrading industrial thermal effluents using multiple-stage vapour jet compressors: Modelling and analysis

Vapour jet compressors with multiple stages were studied and their performance characteristics with varying number of stages, waste heat temperatures and temperature boosts were obtained. The numerical model of the multiple-stage vapour jet compressor is based on equations obtained by applying the theory of ejectors. Computer simulation proved to be an effective tool for obtaining performance characteristics of multiple-stage vapour jet compressors. Results show that the COP does not necessarily increase with increasing number of ejector stages. Also, opting for a vapour jet heat pump with more than two stages will not contribute to improving its performance within the usual temperature ranges of industrial applications.     

Mechanism of heterogeneous

The present article describes a novel theoretical approach to the mechanism of heterogeneous nucleation of pores in metallic systems. The proposed mechanism is based on the behavior of foreign particles at the advancing solid/liquid (S/L) interface. Foreign substrates act as a barrier to the fluid flow as well as to the diffusion field at the S/L interface, giving rise to enhanced gas segregation and viscous pressure drop. Mathematical analyses have been employed to pre- dict the gas segregation and pressure drop in the gap between the particle and the S/L interface. The equations which arise are solved using available experimental data in the literature. An order of magnitude analysis is done, and it is shown that pressures in the range of the activation barrier (fracture pressure) can be obtained in normal castings. The effect of particle properties and solidification parameters, such as wettability, density, thermal conductivity, solidification rate and morphology of S/L interface, are discussed. A complete assessment of all possible kinds of particles is not possible, since the material values and experimental parameters are not known in most of the cases. To consolidate the mechanism, therefore, further quantitative measurements of material values, interfacial energies in particular, are required on systems of interest.